The present invention relates to a method of qualitative and quantified monitoring of the instant local physical state of a substantially incompressible fluid material such as a liquid or pasty substance (for instance slurry or pulp) and a device for carrying out this method and the various applications and uses resulting from the working of the method and/or device for the automatic control of said physical state. The invention is also directed to the various equipment and systems provided with at least one such device.
In various industrial engineering processes liquid or pasty incompressible fluids such as sludges or pulps are used or produced which, after having undergone a previous elaborating or physical conditioning treatment, are carried or conveyed towards a place of subsequent utilization, consumption, treatment or transformation. In industrial facilities this transport is generally performed through pumping and flow circulation within pipelines or conduits. According to their nature, these fluids exhibit a physical state which may be variable locally with time and distance and which is a function of its instant local density and/or its viscosity and/or its solid matter content, these variable state parameters thus defining and characterizing the instant local consistency of the fluid. It is advantageous to know the instant local consistency of the fluid involved at its place of delivery, or of use so as to be able to monitor and ascertain variations thereof in order to correct them for obtaining a consistency of the desired quality.
There is already known from the prior Belgian Patent No. 902,161, (U.S. Pat. No. 4,705,462) a method consisting of selecting a desired volumetric flow rate, determining in accordance with the desired volumetric flow rate and the available pumping capacity a duration of the intake or filling and discharging or emptying cycle of a pumping chamber or enclosure. Thus, a predetermined time of cycle is set for emptying and filling the pump, with the pump caused to empty when the time of cycle has ended. In this known process a cycle time is employed which may be manually adjusted from time to time as required.
More specifically the prior U.S. Pat. No. 4,705,462 discloses a device comprising a volumetric pump with alternating filling or intake and emptying or discharge, with a driven positive-displacement impeller member performing a reciprocating motion and associated with a mechanical indicator movable between two opposite end positions corresponding to the end positions of intake and force strokes of said member. Associated with the mechanical indicator are position detectors or sensors, each capable of transmitting a signal indicating the presence of said indicator at an end position to a chronometrically adjustable system for operating the pump motor. The operation of the pump motor continues for the preset cycle time. The pump motor applies a constant thrust force to said impeller member for displacing the latter in the direction of delivery of fluid.